I wish to post photos online by URL along with commentary. A second choice is to upload photos but that is more work. The intended use is that I want to post photos, some of which are online, and write some text. It is ok if the public sees the photos.

Not Twitter because the message length is too short and because you cannot enter in a URL but, if you use on online photo, must downloaded then uploaded to Twitter.
Last resort is Wordpress. You can't enter in the URL of the photo but must download it and then upload it to Wordpress.
Various forums, like Flyertalk or other forums. Can do it but the moderators will quickly say "these are not relevant to our website"

Also possible is to put it in Google Docs then share it with others.